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Aux port motor

Craftydan

Hostage Taker of Quads
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#2
On a Receiver? yes, but . . .

If it's a secondary motor, that's how it's done. but a couple of points:

- make sure you remove the middle wire (positve voltage) from the plug and tape it off. Otherwise the BEC in the aux motor will fight with the BEC in the primary motor. you only need one, so don't plug them both in.

- the throttle stick is typically mixed 1:1 to the aux channel so the stick is connected to the channel. if you want thrust differential, you'll need an second and third mix from rudder to the two motor's output channels.

If it's a single motor platform, yes, but it might give you trouble. some receivers require the BEC to be connected to the throttle channel, some don't care. in this respect, if it doesn't work, you can plug power + ground into the throttle channel then split off the signal wire and stretch it over to the aux channel.
 

Craftydan

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#4
I need to be precise here: The second motor's ESC can be plugged into another port. The Rx cannot run a motor without an ESC to provide the metered power. Modern ESCs almost ALWAYS have a BEC, and the power pin on the ESC's RX line is designed to push current, not draw current.

Technically, yes, the ESC (with the power pin removed) could be plugged into any unused port, but beware of native mapping in the transmitters. If you've got a free aux port, use it instead of rud/ail/elv, then mix throttle (and possibly rudder) to that aux port. If you connect to the rudder port without carefully setting up the radio, at best, the ESC won't arm (likely) at worst it'll want to stay at 1/2 throttle whenever you let go of the stick.
 
#5
I have a separate Ni-MH pack for the rx.
The tx-rx package was a cheap one, so I dont think it has native mapping. In the manual it says all ports are neutral when the sticks are in neutral.
I'll watch out for the stuff you warned me about.
 

Craftydan

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#6
NiMh huh? hmmm . . . sounds like older gear. Still useable, but you're likely restrained by what it can do.

So what I hear you saying is the transmitter is not programmable? If so, all it has is the native mapping, and no mixing. A good chance you-can't-get-there-from-here with that gear. The problem with "all ports neutral" is that speed controllesrs have a different "neutral" -- they typically like neutral at 0% where other channels like it at 50%.

Does the package come with an external ESC or is it a brick transmitter (designed with the speed controller built into the receiver)? if it's a brick, then *at best* you could wire the motors together (assuming it wouldn't burn out the speed controller), but otherwise you'll need an ESC to run a second motor, matched to the motor.

Only other crazy option (if I understand what you're equipment is correctly and it's MODE 2), you could remove the centering springs from the rudder stick, get a ESC and plug it in (w/o power pin) to the rudder channel, then either twist the gimbal 45 degrees or hold it at 45 degrees. Full centered throttle becomes the top right, weak left thrust becomes up, strong right thrust becomes right, and off is bottom left.

If the TX is mode 1, you'll do the same w/ the aileron stick/channel instead of rudder, and plug the ailerons into the rudder, flying the tilted dual throttle on the right stick and aile/elv on the left.
 
#7
No.
It is a fully programmable tx-rx system.
The Ni-MH is just for the receiver. Li-poly for the motors.
external ESC, for the motor, it wasnt that cheap.
about 30$ USA.
 

pgerts

Old age member
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#11
The most common to use on a Twin engine Electric is to use a Y-Cable.
If you want differential thrust connected to the rudder it is easy and cheap to use a V-tail mixer (or delta mixer) connected to the throttle and rudder output. A Y-cable from the rudder output allows you to use both rudder and differential thrust.
You do normally want all outputs available for other purposes like bomb (door) drop, gear, lights and others if you have a Twin plane unless you have a tx-rx with really lots of channels and mixes.
 

xuzme720

Dedicated foam bender
Mentor
#13
Interesting! Mode type can be selected with the slider on the rear. I've never seen that kind of setup for swapping mode before...
 

Craftydan

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#14
BB,

Sorry for the lag -- had a quick family trip that dropped me off the net.

No, I haven't heard of it, but there's plenty I haven't heard of and the manual seems fairly well written.

I wouldn't call it fully programmable. That's not an insult to the TX -- it can do more than many other $30 radios, but not much more than what is built in. It's "mixing" functions appear to be fixed to one of 4 basic wing configurations, but no flexibility beyond that. Channel 5 and 6 are what I'd call discrete channels -- they can take one of a very few states, and that's it. The channel 5's servo position is adjustable, but it's only one of those three pre-programed positions.

This removes a lot of options for configuring thrust differential in the radio, but Pgerts once again is spot on -- a v-tail mixer module mounted on the plane between throttle/rudder channel and left-motor/right-motor is the way it was done before we could reprogram the radios on the fly. It should work with a little trimming.
 

rcspaceflight

creator of virtual planes
#15
What are you plans for the two motors?

If you don't need or want differential thrust, then you can just use a Y-cable to connect two ESCs together and control the thrust of both together that way. It's not ideal incase one motor or propeller has more thrust than the other, but should mostly be fine. But if you are doing a pusher/puller set up, then it won't matter at all and differential thrust won't do anything.
 

RoyBro

Senior Member
Mentor
#16
Interesting! Mode type can be selected with the slider on the rear. I've never seen that kind of setup for swapping mode before...
I'll bet the slider engages/disengages some sort of resistance thingie that makes the up/down stick stay where it's put. I'd love to get a look inside. I doubt that it can be too elegant at $30. But you never know. :p
 

xuzme720

Dedicated foam bender
Mentor
#17
I'll bet the slider engages/disengages some sort of resistance thingie that makes the up/down stick stay where it's put. I'd love to get a look inside. I doubt that it can be too elegant at $30. But you never know. :p
Me too. Almost worth the $30 just to have a peek....almost.
 
#18
I was thinking that instead of a rudder, I could just use that channel for differential thrust so I wouldnt create drag.
Also It's kind of fun being able to control two motors separately.
Roybro is correct about the resistance thing in the slider. Thats how the modes are changed
 

RoyBro

Senior Member
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#19
So, in which mode do you fly? Which stick movements would control the thrust and for which motor?
I'm concerned that differential thrust will be difficult to control manually.
 

Craftydan

Hostage Taker of Quads
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#20
Roybro,

If BB uses a v-tail/delta mixer module on the plane, he wouldn't control each manually. Throttle channel input would mix to the sum throttle between the two motors, the rudder channel would mix to the differential between the motors. Effectively, the mixer module on the plane would figure it out.

As far as TX mode, pick it on the TX and it no longer matters. BB can connect the rx's throttle to the mixers elevator input, and the rx's rudder to the mixer's rudder input -- the TX's mode setting will be responsible for getting the stick connected to the correct RX channel.